The defense ministers of Japan and Vietnam agreed Tuesday to "strongly oppose" unilateral attempts to change the status quo in regional waters, in a veiled reference to China's maritime expansion.

Meeting in Tokyo, Defense Minister Nobuo Kishi and his Vietnamese counterpart General Phan Van Giang discussed recent developments in the South and East China seas, confirming the two countries will work together to maintain the existing rules-based international order, according to the Japanese Defense Ministry.

Describing such cooperation between the Japanese and Vietnamese defense authorities as having entered a "new level," the two ministers also witnessed the signing of two agreements on cybersecurity and military medicine.